Intershaft Compartment Buffering Arrangement for Gas Turbine Seals
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Solution Overview
Problem
Conventional seals in gas turbine engines fail to operate effectively when exposed to air pressure differences, leading to reduced service lifetime and increased risk of oil leakage due to improper pressurization, especially when air from a low-pressure compressor flows across them, potentially causing operational instability.
Innovation Solution
The system utilizes a high-pressure compressor to provide pressurized air to both radially exterior and interior sides of the seals, ensuring equal pressure and preventing oil leakage by eliminating the need for a separate buffer source, thus maintaining seal functionality and reducing weight and expense.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If air from the low-pressure compressor is used to seal the intershaft compartment, then the seals may not be properly pressurized due to pressure differences, but using a separate buffer source increases device complexity and weight
Solution Approach 1:
The invention extracts and eliminates the separate buffer air source from the system. Instead of using a dedicated buffer source to provide pressurized air to the seals, the system uses air from the high-pressure compressor directly, thereby removing the unnecessary buffer source component and simplifying the overall system architecture while maintaining proper seal pressurization
Solution Approach 2:
The high-pressure compressor air supply serves multiple functions: it provides pressurized air to the seals for proper sealing operation, eliminates the need for a separate buffer source, and simplifies the air supply system. This multi-functional use of HPC air resolves the contradiction by maintaining reliability without requiring additional dedicated components
2Duration of action of stationary object
If conventional seals are used with pressure differences across them, then the seals experience degraded service lifetime and increased risk of failure, but improving seal pressurization requires additional system components
Solution Approach 1:
The invention removes the harmful pressure difference condition across the seals by eliminating the separate buffer source that created unequal pressurization. By using HPC air supply directly, the system ensures proper pressure balance across the seals, extending their service lifetime without adding complexity
Solution Approach 2:
The invention changes the pressure parameter distribution across the seals by using high-pressure compressor air instead of low-pressure compressor air with a separate buffer source. This parameter change ensures equal pressurization across the seal surfaces, preventing degradation and extending service lifetime while simplifying the system
3Reliability
If air flows across the air seals from the buffer source, then the seals may become inoperative and oil leakage risk increases, but preventing this requires maintaining separate buffer sources
Solution Approach 1:
The invention extracts and eliminates the separate buffer source that caused harmful air flow across the seals. By using HPC air supply directly to the intershaft compartment, the system prevents the pressure-driven air flow that would compromise seal operation, thereby improving reliability without requiring additional buffer source components
Solution Approach 2:
The invention converts the potential harm of uncontrolled air flow across seals into a benefit by using HPC air pressure to actively prevent oil leakage and maintain seal integrity. The pressurized HPC air creates a protective environment that prevents harmful air-oil mixing while simplifying the system architecture
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration ensures the seals operate correctly, reduces oil loss, and maintains compartment integrity by using HPC air for intershaft compartment seals, enhancing engine stability and reliability while minimizing weight and cost.
Implementation Method 1
The system may comprise a high pressure compressor that provides pressurized air to a first radially exterior side of the first air seal and to a second radially exterior side the second air seal
Data Source
AI summary
Aspects of the disclosure are directed to a system associated with an engine having a central longitudinal axis, including a first shaft axially extending along the central longitudinal axis, a second shaft coaxial with the first shaft, a first air seal that seals between the first shaft and the second shaft at a first axial location, a second air seal that seals between the first shaft and the second shaft at a second axial location, a first oil seal that provides intershaft sealing between the first shaft and the second shaft at a third axial location, a second oil seal that provides intershaft sealing between the first shaft and the second shaft at a fourth axial location axially adjacent to the third axial location, and a high pressure compressor that provides pressurized air to a first radially exterior side of the first air seal and to a second radially exterior side the second air seal.